[Objective] The spatiotemporal evolution characteristics of mountain-oasis-desert ecosystem service value （ESV） in the Manas River basin from 2000 to 2023,as well as the differences across various landforms were analyzed in order to provide a scientific basis for optimizing land use planning and ecological protection in the river basin,and for formulating regional zoning management and development strategies. [Methods] Land use change information was extracted from remote sensing data spanning from 2000 to 2023.The equivalent factor method was used to assess the ESV across the river basin.Subsequently,correlation analysis was conducted to examine the spatiotemporal evolution characteristics of ESV and its relationships with land use changes. [Results] ① Land use dynamics were characterized by significant cropland expansion （net increase of 3 267.19 km²,total transfer-in of 3 621.11 km²） and grassland contraction （net loss of 3 493.61 km²）.Cropland expansion was predominant in the oasis zone,while the mountainous zone exhibited degradation of natural ecological land.② The total ESV of the river basin exhibited an overall downward trend,with a cumulative loss of 2.74×10¹⁰ yuan over 23 years.A particularly sharp decline （33.90%） was observed from 2005 to 2010.③ Among ESs categories,hydrological regulation value experienced the greatest reduction (1.93×10¹⁰ yuan),while the values of food production,raw material supply,and nutrient cycling increased.④ Spatially,high-ESV zones were concentrated in the southern mountainous glacier region and the Manas Lake region,while desert zones were identified as lowESV zones.The ESV across the three geomorphic zones ranked as follows:oasis zone>mountainous zone>desert zone. [Conclusion] Agricultural expansion-driven land use transition is identified as the primary factor exacerbating the degradation of ecosystem service functions in the Manas River basin.It is recommended to establish geomorphology-based zonal regulation mechanisms.Emphasis should be placed on mitigating the tradeoff between food production and other ecological functions in the oasis zone,ensuring the rational allocation and efficient utilization of scarce water resources,and promoting the orderly management of ecosystem services and the coordinated development of ecology and economy in this arid region.